1. Field of the Invention
This invention relates to a new process for preparing ethylene glycol and lower monohydric alcohols. More particularly, the invention relates to an improved process for preparing ethylene glycol and lower monohydric alcohols from syn gas using a novel catalyst system.
Specifically, the invention provides a new process for preparing ethylene glycol and lower monohydric alcohols from syngas in good yields, which process comprises contacting a mixture of carbon monoxide and hydrogen with a catalyst comprising a ruthenium-containing compound and a special substituted aromatic compound both dispersed in a low melting quaternary phosphonium salt, and heating the resulting mixture at a temperature of at least 150.degree. C. and a pressure of at least 500 psi for sufficient time to produce the desired ethylene glycol and monohydric alcohols.
2. Prior Art
Ethylene glycol is a chemical which has found wide use in industry. It is used, for example, in the preparation of plasticizers for vinyl polymers and as a component in polyester fibers and antifreeze formulations. In view of its many uses, there is a need to find new and more economical methods for preparing the ethylene glycol.
One proposed mode of making ethylene glycol involves the reaction of carbon monoxide with hydrogen in the presence of variously proposed catalyst systems. In general, the mixture of carbon monoxide and hydrogen, commonly known as synthesis gas or syngas, is reacted at elevated temperatures and pressures in the presence of the proposed catalysts. For example, Belgium Pat. No. 793,086 and U.S. Pat. No. 3,940,432, describe the cosynthesis of ethylene glycol and methanol from mixtures of carbon monoxide and hydrogen using a complex rhodium catalyst. U.S. Pat. No. 3,833,634 describes the use of various other metals as catalysts but indicates that only rhodium and cobalt were effective in producing the ethylene glycol.
However, many of these proposed processes are limited by the nature and activity of the catalyst systems. For example, many of the catalyst systems have poor selectivity, have limited solubility and are expensive to prepare.
It is an object of the invention, therefore, to provide an improved method for preparing ethylene glycol and monohydric alcohols. It is a further object to provide a new process for preparing ethylene glycol and monohydric alcohols from syngas using a new catalyst system. It is a further object to provide a new process for preparing ethylene glycol from syngas using an economical catalyst system and one that has good selectivity as to the formation of the desired products. Other objects and advantages of the invention will appear hereinafter.